Unfortunately, it was the "large political confederation" that showed us any sort of real recognition, allbeit very small, it was also that "large political confederation" that attempted to redress the chronic under-investment that Cornwall had suffered under Westminster.
Membership of the EU was/is a double edged sword for Cornwall, overall, I think we would have been better off to have remained. I fear that with the coming of Brexit, the Cornish will be lost in a tide of fascist English nationalism, unless we are very careful, and very vocal. I see no help in that direction coming from westminster.

Everyone, Cornish or otherwise, has their own particular part to play. No part is too great or too small; no one is too old or too young to do something.

Was that in respect of the recognising the Cornish language?
Regarding the EU when, on the other hand, we look at the struggles of the independence movement in Catalonia the EU seems to be completely inadequate to do anything useful such as providing a conciliatory platform to get both sides talking to each other.
But I agree it is not easy to know what is best. I remember those many years ago being duped by the UK government of the day telling us that the EEC was only an economical unit and would never evolve into a political one. We were simply intentionally lied to. BTW The only time I ever got to vote in the UK.